From e8474c2a10be7ca9c8ff1be672017bb55462387b Mon Sep 17 00:00:00 2001
From: Yifan Hong <elsk@google.com>
Date: Mon, 6 Dec 2021 22:44:35 -0800
Subject: [PATCH] storaged: test do not crash on cuttlefish.

If device does not have disk stats, do not crash the
test. Check for null C strings before converting it
to std::string.

Test: storaged-unit-tests
Change-Id: I46c87b6b6876fb0fbdb403c0015886d6d4cca0c6
---
 storaged/tests/storaged_test.cpp | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/storaged/tests/storaged_test.cpp b/storaged/tests/storaged_test.cpp
index 64009c265..004d0b993 100644
--- a/storaged/tests/storaged_test.cpp
+++ b/storaged/tests/storaged_test.cpp
@@ -64,20 +64,23 @@ void write_and_pause(uint32_t sec) {
 } // namespace
 
 // the return values of the tested functions should be the expected ones
-const char* DISK_STATS_PATH;
+const char* get_disk_stats_path() {
+    if (access(MMC_DISK_STATS_PATH, R_OK) >= 0) {
+        return MMC_DISK_STATS_PATH;
+    } else if (access(SDA_DISK_STATS_PATH, R_OK) >= 0) {
+        return SDA_DISK_STATS_PATH;
+    } else {
+        return nullptr;
+    }
+}
 TEST(storaged_test, retvals) {
     struct disk_stats stats;
     memset(&stats, 0, sizeof(struct disk_stats));
 
-    if (access(MMC_DISK_STATS_PATH, R_OK) >= 0) {
-        DISK_STATS_PATH = MMC_DISK_STATS_PATH;
-    } else if (access(SDA_DISK_STATS_PATH, R_OK) >= 0) {
-        DISK_STATS_PATH = SDA_DISK_STATS_PATH;
-    } else {
-        return;
-    }
+    auto disk_stats_path = get_disk_stats_path();
+    if (disk_stats_path == nullptr) GTEST_SKIP();
 
-    EXPECT_TRUE(parse_disk_stats(DISK_STATS_PATH, &stats));
+    EXPECT_TRUE(parse_disk_stats(disk_stats_path, &stats));
 
     struct disk_stats old_stats;
     memset(&old_stats, 0, sizeof(struct disk_stats));
@@ -92,7 +95,9 @@ TEST(storaged_test, retvals) {
 
 TEST(storaged_test, disk_stats) {
     struct disk_stats stats = {};
-    ASSERT_TRUE(parse_disk_stats(DISK_STATS_PATH, &stats));
+    auto disk_stats_path = get_disk_stats_path();
+    if (disk_stats_path == nullptr) GTEST_SKIP();
+    ASSERT_TRUE(parse_disk_stats(disk_stats_path, &stats));
 
     // every entry of stats (except io_in_flight) should all be greater than 0
     for (uint i = 0; i < DISK_STATS_SIZE; ++i) {
@@ -103,7 +108,7 @@ TEST(storaged_test, disk_stats) {
     // accumulation of the increments should be the same with the overall increment
     struct disk_stats base = {}, tmp = {}, curr, acc = {}, inc[5];
     for (uint i = 0; i < 5; ++i) {
-        ASSERT_TRUE(parse_disk_stats(DISK_STATS_PATH, &curr));
+        ASSERT_TRUE(parse_disk_stats(disk_stats_path, &curr));
         if (i == 0) {
             base = curr;
             tmp = curr;